Myriad types of fragrance delivery systems are available on the market. Each system is designed to deliver a volatile chemical to a local environment, and, in general, conventional air freshener articles are constructed based on an article engine, where a volatile chemical composition is contained in a reservoir and emitted from the reservoir, either by the natural volatilization process or by a positive-forced emission, and where the volatile chemical composition is exposed to a source of heating or a forced stream of air to promote emission to the environment. Such systems vary in simplicity of design. Much more complex systems contain separate compartmentalized reservoirs of volatile chemicals, wherein volatilization and delivery into the environment are mechanically controlled and driven.
Generally, the chemical composition contained in a fragrance delivery system is described as a perfume, and a perfume can be any chemical or mixture of chemicals that upon volatilization either as a vapor or as microdispersed droplets, delivers an attractive or pleasing odor to a localized space. The technology of perfume composition creation is well known and described in the literature, such as, the book by S. Arctander, Perfume and Flavor Chemicals (1969, Montclair, N.J., USA). Also, there is an abundant wealth of patent literature available in the field of perfumery.
Conventionally, a perfume or chemical fragrance composition contains a complex mixture of volatile ingredients of natural or synthetic origin belonging to various chemical classes of compounds, including alcohols, aldehydes, ketones, esters, ethers, acetates, nitriles, terpene hydrocarbons, nitrogen or sulfur heterocyclic compounds and essential oils. These volatile materials, often characterized as aromachemicals may be compounded in a supporting chemical base that includes solvents and other ingredients selected depending upon the specific utility to which the final composition is directed. The final fragrance composition is often a complex mixture of multiple aromachemicals dissolved or dispersed in a carrier solvent base, which may be a mixture of solvent and volatile assistants compounded to optimize the release of the fragrance to the environment.
In most cases, the ideal goal of the fragrance delivery system is to provide a consistent release of the fragrance over the scheduled lifetime of the air freshener article. Such consistent release is herein referred to as a “linear release” and is employed to describe a concept whereby a consumer perceives the emitted scent from the article to be identical from a standpoint of quality and intensity throughout the prescribed lifetime of the article. In practicality, this ideal is difficult to achieve because aromachemicals of the fragrance composition have differing vapor pressures and differing threshold values at which a person perceives the odor of the aromachemical. Additionally, and important to the design of the aroma release engine system, consumers have differing abilities to detect the various aromachemicals, and this issue is compounded by effects of differing environmental conditions, i.e., temperature, air flow, humidity, volume of emission space, in which the fragrance dispenser is located.
Against such a complex set of issues, there have been many attempts to provide a fragrance release system that is simple in design, and reasonably low in cost yet effective in provision of a linear performance of perceived air-freshening effect.
U.S. Pat. No. 2,629,628 (Vaillancourt) (Feb. 24, 1953) describes an insect repellant attachment to be placed on a screen door. The device is constructed of a planar base of a suitable material such as heavy cardboard and a pad of absorbent material secured to the pad. The base extends beyond the pad in at least one direction and includes an eyelet or hole for insertion of a looped cord, which allows for hanging the device from a nail or hook on the screen door. The pad is saturated with the repellant, which upon normal opening and closing motion of the door, is dispersed from the pad.
U.S. Pat. No. 4,419,395 (Sugimoto) (Dec. 6, 1983) describes a perfumed pendent having a three-dimensional configuration. The pendant is constructed of a front vinyl sheet printed with a design and a back vinyl sheet mated to the front sheet, and the two sheets are welded to one another along an outer peripheral edge. A foam pad is interposed between the sheets to provide three-dimensional form. A capsulated perfume layer is laminated to the outer surface of the front sheet. The capsulated perfume layer contains a plurality of capsules containing perfume which are secured to the sheet surface by a binder. The perfume is released via scratching of a finger, for example.
WO 93/00115 (Fischel-Ghodsian) (Jan. 7, 1993) describes a device for controlled release of vaporous medications or repellants that is a multilayered laminate having, in order from the rear, an adhesive layer for fixing the device to a surface, an impermeable membrane layer, a reservoir layer incorporating the active material and a diffusion rate limiting layer on the front surface. The impermeable layer is described as a metal foil polymer laminate, wherein the polymer is selected from polyethylene terephthalate, polyethylene, polypropylene, polyvinyl chloride and ethylene vinyl acetate. The reservoir layer is made of a porous polymer, an impregnated polymer or a gelled polymer mixture.
U.S. Pat. No. 5,282,571 (Smith et al.) (Feb. 1, 1994) describes a plastic automobile sun visor clip, wherein the plastic material is impregnated with an aroma-creating material. The clip is molded via a combination of plastics, including a product described as POLYIFF, which is described as a fragrance impregnated plastic obtained from International Flavors and Fragrances, Inc.
U.S. Pat. No. 5,820,791 (Canale) (Oct. 13, 1998) describes an air freshening device to be used in conjunction with an air circulation system. The device is a molded object shown in one embodiment as a grid of rectangular intersecting plastic pieces, wherein the plastic is a combination of conventional plastic and scent impregnated plastic.
WO 03/097114 (Jean et al.) (Nov. 27, 2003) describes a molded thermoplastic article consisting of a decorative face and a plastic replaceable element that is impregnated with a volatile active ingredient such as a perfume. The resin of the element is a volatile impregnated polyether-ester-amide type plastic identified under the commercial name “PEBAX.” The element is attached to a fixing system, which associates the device with a ventilation or air conditioning system.
U.S. Pat. No. 6,938,832 (Sada) (Sep. 6, 2005) describes a scent strip that is constructed with a back adhesive layer, a layer of porous material containing the active material and a peelable protective cover layer. The strip is intended to be adhered to a surface of an entertainment medium such as a DVD box and, upon cue from the medium, the cover is peeled off to release the volatile and thus enhances the entertainment experience.
US 2008/0105760 (Sheffield et al.) (May 8, 2008) describes an aromatic device having a volatile-impregnated decorative and/or shaped unit on a suction cup for adherence to a flat surface.
U.S. Pat. No. 7,159,792 (Wheatley et al.) (Jan. 9, 2007) describes an air freshener that can be removeably adhesively attached to a surface so as to be capable to locate and relocate where needed. The device consists of a scent portion and attachment portion. The scent portion contains an active carrier material, such as a polymer or polymer gel, that is freestanding and contains an active, such as scented oil. The polymer body is compressible under an applied force and substantially returns to its original shape when the force is removed. Polyurethane or polyurethane gel is described as an example of a carrier material. The attachment portion includes a pad formed of a material that imparts a “clingy, tacky or frictional quality,” which provides surface adhesion. The shape and size of the scent portion can be configured to determine the amount and rate of scent release.
US 2009/0072045 (Wheatley et al.) (Mar. 19, 2009) describes an air freshener device having a head as described for the scent portion of U.S. Pat. No. 7,159,792 pivotally combined with a vent rod for insertion into a vehicle air vent.
US 2010/0065654 (Wheatley et al.) (Mar. 18, 2010) describes an air freshener device having a basic head as described for the scent portion of U.S. Pat. No. 7,159,792 and vent rod as described in US 2009/0072045. However, the device contains multiple rods and multiple heads which are arranged to form a decorative display.
US 2011/0108632 (Brandenburg et al.) (May 12, 2011) describes an air freshener clip that is removeably engaged with a louver or slat of a vent. The clip is constructed of a base plastic which is covered with an outer portion of a plastic that has been compounded with a fragrance material prior to injection molding.
US 2012/0067970 (Hossein) (Mar. 22, 2012) describes an air freshener having a support element and a decorative element associated with the support element. The support element is designed for insertion into a grille, and the decorative element has a thermoplastic polymer matrix that contains a scent agent to be spread to the environment. An example of the decorative element is one constructed of 70-72% by weight ethylene vinyl acetate and 28-30% scent agent. The support element may be detachable from the decorative element.
EP1704874 (Barthel et al.) (Sep. 27, 2006) describes an aroma dispenser constructed for attachment to vents of appliances such as a home computer. The dispenser contains an attachment portion that is arched when fitted to the appliance. Air exiting the vent passes through the arch into a receiving space containing a scent delivery system, consisting of spherical particles of a polymeric carrier material and a fragrance in the form of a perfume oil. An example of the carrier material is ELVAX 150 from DuPont. A loading of 30-35% is possible with the ELVAX 150. Methods for adhering the scent-dispensing portion to the fastener portion of the device include an adhesive layer and a Velcro fastener.
In spite of the various efforts to provide a fragrance release system described above, there remains a need for a fragrance release system that is economical and simple in construction and can be adapted to have utility in many environmental applications, and preferably, effectively provides a linear release of aromachemical over the lifetime of the article.